I'm going outside the box, somewhat, for
Hated character in show you love.
There have been many hated characters in the world of professional wrestling. The King of them all was clearly
Bobby "The Brain" Heenan.
To put him in a specific show, I will choose the
Superstars of Wrestling. I actually saw him, and learned to hate him, before that.
Superstars really cemented my feeling, even as it was more open that the matches were scripted, and everyone was a player. Heenan played the role perfectly.
He was the ultimate Heel, primarily as a manager, but also as a wrestler. He was not averse to getting in the ring and taking a bump to get a pop from the audience. His other nickname, "The Weasel", came from a match with Greg Gagne wherein Gagne beat him up and put him in a weasel suit. Later, Ultimate Warrior did the same thing.
Nobody was a better heel; nobody was as hated for as long as "The Weasel" Bobby "The Brain" Heenan.